If you cheat in a test, you've really only cheating yourself.
如果你在测验中作弊的话,你欺骗的只有你自己。
Birds of a feather flock together.
物以类聚,人以群分。
Up to now, historians have assumed that calendars came into being with the advent of agriculture, for then man was faced with a real need to understand something about the seasons.